Methods and system for controlling an illuminating apparatus

ABSTRACT

This invention provides an improved digital luminance controlling system, which can control the luminous intensity of an illuminating apparatus by choosing the number of the ignited luminaries. It optimizes the number of the ignited luminaries according to the different contribution rate of each luminary to the general luminous intensity to reduce the power consumption. By properly adjusting the sampling frequency of the luminous intensity of the circumstance, this invention could decrease the operating frequency of the luminance controlling system, thereby to further reduce the power consumption. This invention also provides a analog type of the luminance controlling system, which consists of a optical sensing apparatus, a analog type of the luminance controlling apparatus and a set of optical source and can realize a real time luminance adjustment, to reduce the power consumption.

FIELD OF THE INVENTION

The present invention relates to a luminance controlling system,particularly to an adaptive system that could automatically adjust itsown luminous intensity according to the luminous intensity of acircumstance. As used herein, the term “circumstance” refers to ambientlight as sensed by the system.

BACKGROUND OF THE INVENTION

Electronic devices such as mobile phone, PDA (Personal DigitalAssistant), pager, etc. usually have a display screen, which is mostly aliquid crystal displaying apparatus that could make the content to bedisplayed visible by providing backlights when the luminous intensity ofthe circumstance is not high enough. Meanwhile, these electronic devicessuch as mobile phone and PDA (Personal Digital Assistant) may also havea data inputting apparatus comprising a set of keys, and the devicesmake the keypad visible through backlights when the luminous intensityof the circumstance is not high enough.

FIG. 1 is the prior art digital luminance controlling system. The systemis a technical solution disclosed in the U.S. Pat. No. 5,760,760(granted on Jun. 2, 1998), comprising a light sensing apparatus 110, adigital luminance controlling apparatus 120, a light source controllingapparatus 130 and a group of light sources 140, with the digitalluminance controlling apparatus further comprising an analog-to-digitalconverter (ADC) 122, a digital signal processor (DSP) 124 and a memory126. When the light sensing apparatus 110 detects the luminous intensityof the circumstance, it sends an signal of the luminous intensity of thecircumstance to the digital luminance controlling apparatus 120, and theanalog signal is converted into digital signal in accordance with apreset sampling frequency by the analog-to-digital converter 122 and thedigital signal is sent to the digital signal processor 124, and thedigital signal processor 124 reads the luminance level in the memory 126according to the digital luminous intensity signal and converts it intoa luminance controlling signal to be sent to the light control device130 which adjusts the luminance of the light source according to thereceived luminance controlling signal.

FIG. 2 is the light source controlling apparatus of the prior artdigital luminance controlling system. The device is a technical solutiondisclosed in the British Patent GB2, 365, 691 (published on Feb. 20,2002), comprising a group of selection switches (S₁, S₂, . . . , S_(N))and M groups of resistors (R₁₁, R₁₂, . . . , R_(1N); R₂₁, R₂₂, . . . ,R_(2N); . . . ; R_(M1), R_(M2), . . . , R_(MN)), with the number ofresistors in each group of resistors depending on the number ofselection switches, i.e., on the number of luminance levels. The groupof selection switches and M groups of resistors are connected to a lightsource, i.e., an illuminating apparatus comprising a group of luminaries(L₁, L₂, . . . , L_(M)) (such as light-emitting diodes), in such amanner that each switch, such as S₁, is connected to a group ofresistors (R₁₁, R₂₁, . . . , R_(M1)) and the luminaries (L₁, L₂, . . . ,L_(M)), wherein the number of resistors in the group of resistorsdepends on the number of the luminaries, and wherein the resistors aredirectly connected to the luminaries. By setting different switches tothe connection state, the currents through the luminaries or thevoltages applied to the luminaries are made different, thereby, theluminance of the luminaries is adjusted.

Since the number of luminance levels in the prior art is limited by thenumber of the selection switches, with the increasing of luminancelevels, the number of selection switches and the number of the groups ofthe resistors increase simultaneously, thus the selection of the numberof luminance levels is obviously limited while the corresponding costincreases. Therefore, the object of reducing power consumption bychanging the luminance more smoothly with the change of the luminousintensity of the circumstance cannot be achieved.

Hence, an improved luminance controlling system is needed, which couldchange the luminance more smoothly with the change of the luminousintensity of the circumstance so as to achieve the objects of reducingpower consumption and saving cost.

SUMMARY OF THE INVENTION

The present invention provides an improved digital luminance controllingsystem, in a light source controlling apparatus thereof, the resistorand the luminaries are connected by a switch, thus the luminance of theilluminated area could be controlled by selecting the number of theignited luminaries. By reducing the number of the ignited luminaries,the power consumption could be reduced.

The present invention further provides an improved digital luminancecontrolling system, and a digital luminance controlling apparatusthereof compares two successively detected values of the luminousintensity of the circumstance. If the difference between the values issmaller than a predetermined value, the sampling frequency is decreased,and if the difference is greater than another predetermined value, thesampling frequency is increased. By adjusting the sampling frequencytimely, the luminance controlling system could operate less frequentlyand thereby the power consumption could be reduced.

The present invention further provides an analog luminance controllingsystem, comprising a light sensing apparatus, an analog luminancecontrolling apparatus and a group of light sources. When the lightsensing apparatus detects the luminous intensity of the circumstance, itsends an signal of the luminous intensity of the circumstance to theanalog luminance controlling apparatus, and the signal of the luminousintensity of the circumstance is converted into luminance controllingsignal according to a preset magnification by the analog luminancecontrolling apparatus, and the controlling signal is applied to thelight source in the form of current or voltage to adjust the luminanceof the light source. Since the luminance controlling apparatus works inan analog manner, real-time luminance adjustment could be realized, andthus the power consumption is reduced. Meanwhile, since theanalog-to-digital converter (ADC), the digital signal processor (DSP),the memory and the light source controlling apparatus are not needed anymore, the objects of saving costs and further reducing power consumptioncan be achieved.

The other objects and achievements of the present invention will beobvious by referring to the following descriptions made with referenceto the figures and the claims which will be helpful for betterunderstanding of the present invention.

DESCRIPTION OF THE DRAWINGS

The present invention is explained in detail in the form of embodimentswith reference to the figures, wherein,

FIG. 1 is the prior art digital luminance controlling system;

FIG. 2 is the light source controlling apparatus of the prior artdigital luminance controlling system;

FIG. 3 is the digital luminance controlling apparatus of an embodimentof the present invention;

FIG. 4 is the schematic plan view of a group of luminaries composing theilluminating apparatus of an embodiment of the present invention;

FIG. 5 is a digital luminance controlling apparatus of anotherembodiment of the present invention;

FIG. 6 is the flow chart of the operating process of the digitalluminance controlling system of an embodiment of the present invention;

FIGS. 7A and 7B are the analog luminance controlling system of anembodiment of the present invention;

FIGS. 8A and 8B are the analog luminance controlling system of anotherembodiment of the present invention;

FIG. 9 is the flow chart of the operating process of the analogluminance controlling system of an embodiment of the present invention.

In all the figures, the same reference numerals indicate the same orsimilar features and functions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3 is the digital luminance controlling apparatus of an embodimentof the present invention. In the figure, a group of selection switches(S₁, S₂, . . . , S_(N)) is connected between the resistors (R₁, R₂, . .. , R_(N)) and the luminaries (L₁, L₂, . . . , L_(N)) that compose theilluminating apparatus, and a corresponding number of luminaries can beset to the ignited state by setting different numbers of switches to theconnection state, and thereby to make the light source comprising thegroup of luminaries provide the desired luminance in the illuminatedarea. Compared with the prior art technical solution as shown in FIG. 2,the embodiment could greatly reduce the number of resistors needed andthe complexity of the circuits while maintaining the same luminancecontrolling level, thus the power consumption is reduced.

FIG. 4 is the schematic plan view of a group of luminaries composing theilluminating apparatus of an embodiment of the present invention. In thearea that needs to be illuminated, there is an illuminating apparatuscomprising a group of nine luminaries (L₄₁, L₄₂, . . . , L₄₉), and thearrangement of the luminaries is shown in the figure. It can be seenfrom the figure that luminaries in different positions contributedifferently to the general luminous intensity of the illuminated areaunder the same illuminating conditions (the same rated power, the samecurrent, etc.), for example, L₄₅ contributes more than L₄₄, and L₄₄contributes more than L₄₁ and so on. Thus it is possible to select theleast number of luminaries that are in the ignited state by using aparticular algorithm according to the different contribution rates ofeach luminaries to the general luminous intensity of the illuminatingapparatus so as to achieve the desired general luminous intensity, thusthe power consumption is reduced. For instance, under the sameilluminating conditions, the light source comprising L₄₂+L₄₄+L₄₆+L₄₈could achieve the same general luminous intensity as the light sourcecomprising L₄₁+L₄₃+L₄₅+L₄₇+L₄₉.

Furthermore, luminaries of different rated illuminating power could beselected according to the different contribution rate of each luminaryto the general luminous intensity, and resistors of different resistancevalues could be selected to be connected to different luminaries,thereby, different luminaries could have different luminous intensityunder the same luminance controlling signal.

In addition, some electronic devices, such as mobile phone, PDA(Personal Digital Assistant) etc., may have a display screen and a datainputting apparatus comprising a set of keys, and in the samesurrounding environment, the luminous intensity of the illuminatingapparatus under the control of the luminance controlling apparatus couldbe different in the display screen and in the area of data inputtingapparatus, and thus the power consumption is further reduced.

FIG. 5 is a digital luminance controlling apparatus of anotherembodiment of the present invention, the digital luminance controllingapparatus is an improvement based on the technical solution of FIG. 3.On the basis of the technical solution of FIG. 2, a group of switches(S_(N+1), S_(N+2), . . . , S_(N+M)) is added between M groups ofresistors (R₁₁, R₁₂, . . . , R_(1N); R₂₁, R₂₂, . . . , R_(2N); . . . ;R_(M1), R_(M2), . . . R_(MN)) and luminaries (L₁, L₂, . . . , L_(M)),thus compared with the technical solution of FIG. 2, the presentembodiment could have more luminance controlling levels available forselection, so that the luminance could be changed more smoothly with thechange of the luminous intensity of the circumstance so as to achievethe object of reducing power consumption.

FIG. 6 is the flow chart of the operating process of the digitalluminance controlling system of an embodiment of the present invention.The display screens of electronic devices such as mobile phone, PDA(Personal Digital Assistant) have different states. In the presentembodiment, there are two different types of states, i.e., the ignitingstate and the non-igniting state, wherein the igniting state is theworking state that needs manual intervention and the non-igniting stateincludes the stand-by state and working state that does not need manualintervention, etc. The working state that does not need manualintervention is, for example, the state of data exchanging with thecomputer or network and the state of calling for a long time, etc.

The electronic devices are usually in the non-igniting state, and whenthe state changes to an igniting one (step S620), the luminancecontrolling system first detects the luminous intensity of thecircumstance (step S630) and then preliminarily sets the luminousintensity of the illuminating apparatus of the system according to theluminous intensity of the circumstance (step S642) while initializingthe luminous intensity of the circumstance sampling frequency (stepS646). In step S642, the luminous intensity of the illuminatingapparatus of the system could be set to zero according to the luminousintensity of the circumstance, i.e., not using the illuminatingapparatus of the system.

Afterward, when the next sampling time is up (step S650), it isdetermined whether the electronic device is in the igniting state (stepS660). If it is, again the luminance controlling system detects theluminous intensity of the circumstance (step S670) and sets the luminousintensity of the illuminating apparatus of the system according to theluminous intensity of the circumstance (step S680), and if it is not inthe igniting state, the whole system is set to the non-igniting state.

When the sampling has been performed twice or more, each new sampledvalue of the luminous intensity of the circumstance is compared with itsprevious sampled value of the luminous intensity of the circumstance(step S690). If the absolute value of the difference is smaller than acertain preset value Value 1 (e.g., 2 lux), the sampling frequency ofthe luminous intensity of the circumstance is reduced based on thedifference (step S696); if the absolute value of the difference isgreater than a certain preset value Value 2 (e.g., 10 lux), the samplingfrequency of the luminous intensity of the circumstance is increasedbased on the difference (step S692), wherein Value 2>Value 1; and if theabsolute value of the difference is between the preset value Value1 andValue2, the sampling frequency of the luminous intensity of thecircumstance remains the same (step S694).

In the end, return to step S650 according to the adjusted samplingfrequency of the luminous intensity of the circumstance. When the nextsampling time is up, it is determined again whether the electronicdevice is in the igniting state, and the above process will be repeated.

FIG. 7 is the analog luminance controlling system of an embodiment ofthe present invention. The analog luminance controlling system comprisesa light sensing apparatus 710, an analog luminance controlling apparatus720 and a group of light sources 730. The analog luminance controllingapparatus further comprises a mapping amplifying circuit 726, acontroller 722 with timing function and a switch 724.

When the light sensing apparatus 710 detects the luminous intensity ofthe circumstance, it sends a signal of the luminous intensity of thecircumstance to the analog luminance controlling apparatus 720. When theelectronic device employing the analog luminance controlling system isin an igniting state, the controller 722 with timing function sends anactivating signal to set the switch 724 to the connection state, thenthe signal of the luminous intensity of the circumstance is convertedinto luminance controlling signal according to the preset reversemagnification by the analog luminance controlling apparatus and thecontrolling signal is applied to the light source in the form of currentor voltage to adjust the luminance of the light source.

The reverse magnification of the present embodiment is shown in thecurve 760 of the figure. The curve is continuously changed in real-timewhile the higher the luminous intensity of the circumstance is, thelower the luminous intensity of the system itself. The reversemagnification could be preset by the manufacturer of the electronicdevice or by the user. The luminance controlling system having anreverse relationship with the luminous intensity of the circumstancecould be applied to electronic devices providing backlights, such as theliquid crystal display screen of the mobile phone, etc., wherein thehigher the luminous intensity of the circumstance is, the lower thebacklights intensity of the display screen. When the luminous intensityof the circumstance is greater than 100 lux, the backlights intensity ofthe display screen is zero, i.e., the illuminating apparatus of thesystem is not in use.

Accordingly, in the preceding digital luminance controlling system, theluminance controlling signal sent by the digital luminance controllingapparatus and the luminous intensity of the circumstance could also havea reverse relationship, and the reverse relationship could also bepreset by the manufacturer of the electronic device or by the user,except that it is a non-continuous grading distribution.

As for the analog luminance controlling system, luminaries of differentrated illuminating power could be selected according to differentcontribution rate of each luminary to the general luminous intensity ofthe illuminated area. Resistors of different values could also beselected to be connected to different luminaries, and thereby differentluminaries could have different luminous intensity under the sameluminance controlling signal.

In addition, some electronic devices, such as mobile phones, PDA(Personal Digital Assistant), etc., have a display screen and a datainputting apparatus comprising a set of keys. The luminous intensity ofthe light source under the control of the luminance controllingapparatus could be different in the display screen and in the area ofdata inputting apparatus while they are in the same environment, andthus the power consumption is further reduced.

FIG. 8 is the analog luminance controlling system of another embodimentof the present invention. The system differs from the analog luminancecontrolling system of the embodiment in FIG. 7 by that the analogluminance controlling apparatus 820 mapping amplifies the signal of theluminous intensity of the circumstance into the luminance controllingsignal according to the preset positive magnification and applies it tothe light source 830 in the form of current or voltage to adjust theluminance of the light source.

The positive magnification of the present embodiment is shown as curve860 in the figure. The curve is continuously changed in real-time whilethe higher the luminous intensity of the circumstance is, the higher theluminous intensity of the system itself. The positive magnificationcould be preset by the manufacturer of the electronic device or by theuser. The luminance controlling system having a positive relationshipwith the luminous intensity of the circumstance could be applied toself-illuminating electronic devices, such as traffic lights on theroads, wherein the higher the luminous intensity of the circumstance is,the higher the luminous intensity of the traffic lights so as tofacilitate recognition.

Accordingly, in the preceding digital luminance controlling system, theluminance controlling signal sent by the digital luminance controllingapparatus and the luminous intensity of the circumstance could also havepositive relationship, and the positive relationship could also bepreset by the manufacturer of the electronic device or by the user,except that it is a non-continuous grading distribution.

FIG. 9 is the flow chart of the operating process of the analogluminance controlling system of an embodiment of the present invention.Electronic devices are usually in the non-igniting state, and when thestate changes to an igniting one (step S920), the controller with timingfunction sets the switch to the connection state to set the luminancecontrolling apparatus to the working state (step S930). At this point,the system sends luminance controlling signal according to the detectedluminous intensity of the circumstance, and the luminance controllingsignal could adjust the luminous intensity of the illuminating apparatus(step S940). In step S940, the luminous intensity of the illuminatingapparatus of the system could be set to zero according to the luminousintensity of the circumstance, i.e., not using the illuminatingapparatus of the system.

Subsequently, the timer in the controller is set to the working state(step S950). When the timing is over, i.e., when the next detection timeis up (step S962), it is determined whether the electronic device is inthe igniting state (step S966). If so, return to step 950 to repeat theprocess until the electronic device is in the non-igniting state. Ifnot, the controller sets the analog luminance controlling apparatus to astand-by state (step S970) and then returns to step S910. The durationin which the timer of the controller is in the working state is presetby the manufacturer of the electronic device or by the user.

Although the present invention has been described in detail withreference to the embodiments, it is obvious for those skilled in the artto make substitutions, modifications and variations on the basis of theabove descriptions. Therefore, if such substitutions, modifications andvariations should fall into the spirit and scope of the appended claims,they should be included in the present invention.

1. A system for controlling an illuminating apparatus comprising aplurality of luminaries, the system comprising: a sensing apparatus forsensing the luminous intensity of a circumstance; and a light sourcecontrolling apparatus for controlling the luminous intensity of saidilluminating apparatus, wherein: each luminary of said plurality ofluminaries has a predetermined luminance output, said sensing apparatussamples the luminous intensity of the circumstance and communicates asignal associated with a value of said luminous intensity to said lightsource controlling apparatus, and said light source controllingapparatus activates a number of luminaries of the plurality ofluminaries based at least in part on said value of the luminousintensity.
 2. The system according to claim 1, wherein said light sourcecontrolling apparatus activates said number of luminaries based on acontribution of each of said luminaries to a general luminous intensityof said illuminating apparatus.
 3. The system according to claim 1,wherein said sensing apparatus adjusts a sampling frequency according toa change in said luminous intensity of the circumstance.
 4. The systemaccording to claim 1, wherein each of said multiple luminaries has atleast two predetermined luminance outputs and said light sourcecontrolling apparatus activates one of said predetermined luminanceoutputs corresponding to said luminous intensity of the circumstance. 5.A method for controlling the illuminating apparatus comprising aplurality of luminaries comprising the steps of: sampling a luminousintensity of a circumstance; generating a control signal associated witha sampled value of said luminous intensity; and activating a number ofthe luminaries of the plurality of luminaries based at least in part onsaid control signal.
 6. The method according to claim 5, furthercomprising the step of selecting said number of the luminaries based ona contribution of each of said luminaries to a general luminousintensity of said illuminating apparatus.
 7. The method according toclaim 5, wherein a frequency of said sampling is adjusted based on achange in said luminous intensity of the circumstance.
 8. The methodaccording to claim 5, wherein each of said multiple luminaries has atleast two predetermined luminance outputs, the method further comprisingthe step of activating one of said predetermined luminance outputscorresponding to said circumstance luminous intensity.
 9. A system forcontrolling an illuminating apparatus incorporating at least oneluminary comprising: a sensing apparatus; and a light source controllingapparatus; wherein said luminary has a predetermined luminance output ata predetermined power consumption, said sensing apparatus communicatesto said light source controlling apparatus an analog signalcorresponding to a luminous intensity of a circumstance, and said lightsource controlling apparatus adjusts the power consumption based atleast in part on said analog signal.
 10. The system according to claim9, wherein said light source controlling apparatus adjusts the powerconsumption corresponding to said analog signal by regulating anelectric current affecting said luminary.